Abstract: In order to meet the demand of temperature deformation, generally only one fixed-pier is set in a continuous bridge. As a result, unfortunately, all the longitudinal seismic loads are applied to one fixed pier, which may result in the damage of the fixed pier and the expansion joint, and even lead to a falling-off. For this reason, an acceleration activating locking dowel is developed. The device is designed to be installed between the piers and beams, which can prohibit the relative displacement between the sliding piers and the bridge once the earthquake occurs and help the piers to collaboratively bear the longitudinal seismic force,thus reduce the seismic response. Meanwhile, a case study of a practical project is conducted to illustrate the damping effect of the locking dowel and its influence factors. According to the research results, the locking dowel can significantly reduce the seismic actions on the fixed pier and the relatively displacement between the sliding piers and the bridge, and thus improve the seismic performance of a continuous bridge. Besides, the damping effect of the device is mainly determined by the acceleration activating threshold and locking clearance.